Lights for hallways, storerooms, basements, and other seldom-occupied or pass-through areas are often left ON with the result that not only is a vast amount of electricity wasted, but also the useful lifetimes of the light bulbs which light the area are consumed unecessarily. Aside from the obvious cost of wasted electricity and the price of light bulbs, the very real labor cost for light bulb replacement is higher than might be realized, in the event that someone has to be hired to replace the burned-out bulbs, such as would be the usual case in apartment complexes, hospitals, offices, and similar commerical or business applications.
Dimmers, or higher-voltage (e.g., so-called "long life" or "130 volt") light bulbs, are sometimes used to cut the amount of light in these seldom frequented areas, but the result is usually a less than desirable level of lighting in both the aesthetic and security aspect. For example, when turning ON the light in a store-room or hall-way, it is desirable to have a good bright light in order to discourage any would-be attackers and, in general, to help the person gain quick visual orientation. Therefore, if the lights are merely permanently dimmed, the dull lighting conditions can lead to problems of safety, or at least a nerve wracking fear of there being a lack of safety, for any person using the area.
Aside from general building lighting, whether for security or appearance, there are other utilitarian applications for time-out switches which may better be served by a timer which does not abruptly switch from a bright level of illumination to full darkness. For example, the room occupied by an infant (or an infirm or elderly person) may best be served by having a switch which is capable of automatically dimming the light level after a finite period of brightness. This kind of lighting can enable a gentle sleep-inducing mood: and of course the DIM period may then be followed by darkness, if desired. Domestic garages are another area where the bi-level illumination is of good advantage. The light may be brought ON bright when the person enters the garage, whilst it assumes a DIM level soon thereafter: after the owner has driven away, for example. Also the device as I teach it can be hooked together with an automatic garage door opener to turn the lights full ON whenever the opener is actuated, while again dimming down some time later again. Maintaining the DIM level also serves to ward off prowlers without maintaining the stark, bulb-consuming bright illumination level otherwise had if the lights are merely left ON.
The desirability for automatically turning-OFF the lights after a period of time certainly has been addressed before by timing devices manufactured by several companies. For example, Paragon Electric Mfg. Co. of Twin Rivers, Wis. makes a model ET-600 "Switch Command" which allows a person to turn a room light ON, whereupon after ten or more minutes it will automatically turn the lights OFF . . . BANG, right into darkness! Intermatic Incorporated of Spring Grove, Ill. also produces a model EI-15-MH which does about the same thing. Also, this later company produces a model EJ-341 (which appears to have been derived from a model WT-341 timer made by Dynascan Corporation of Chicago, Ill.) that, while being adjustable in-so-far as timing periods are concerned, still plunges a controlled area immediately into full darkness when it reaches the OFF state. Thus it can be seen that a previous awareness of the problems of leaving lights ON unattended has been recognized to be of such significance as to justify substantial investment in the manufacture of products intended to overcome the underlying human nature problem of forgotten or otherwise left-on lights. The resulting performance of these earlier time switches is, however, rather severe in that having an area abruptly pitched into total darkness by a timed-out switch can lead to, at best, much frustration for any persons remaining in the area: both in the sense of mere inconvienence, and more importantly in regards to being put in a queazy situation involving their personal safety and wellbeing. As a result of the shortcomings found in these earlier devices, consumer resistance is encountered which serves to inhibit more universal application, and the resulting strong economic viability of this type of device as a product for any of the several manufacturers.
I observed the shortcomings of these earlier devices and then I realized that the mere dimming-down of the light level would serve to conserve electricity and save light bulb wear and tear, and at the same time prevent the undesirable pitching of the area into darkness. Instead of abruptly shutting off, area lighting would just be reduced to a DIM level from which a person can still safely exit. I also realized that, in order to be useful in older (pre-existing) installations, the circuitry associated with any timing device needs to work on one side of the line, like an ordinary wall switch. In effect, the device must be a two-lead configuration. While in my earlier U.S. Pat. No. 4,336,464 I do teach a "two terminal timed electric switch", I fall short of predicting the advantage now brought forth in obtaining a dimmed-down second state, in lieu of just simply shutting the lights OFF. This earlier patent does discuss the desirability for two-terminal operation, however. Furthermore, the mentioned Paragon and Intermatic timers operate as two-terminal devices on but one side of the line, in recognition of common domestic and commercial wiring practices (i.e., only two wires brought to a switch location).
I also have taught, in my U.S. Pat. No. 4,300,090 a "direct current power supply" that produces d.c. potential derived from current flow through one side of an a.c. power circuit. The essence of this power supply also served in my U.S. Pat. No. 4,336,464 as a source of d.c. potential for the timing circuits.
It is through the utilization of the essence of this d.c. power supply, combined with several new method and embodiment features, that I have now obtained a novel and efficient timer having capability for dimming down ordinary incandescent lights while working with but one side of a regular a.c. power circuit.
The timed switch I now teach also is shown to be operable in three states: (1) BRIGHT; (2) DIMMED Down; (3) OFF whereby a substantial period of full light BRIGHTness is followed by a goodly period of DIM lighting. After the elapse of the DIM lighting period, the light is shut OFF completely. This variation is of course particularly suited for those uses where even the power waste of an unattended DIM light is undesirable, such as in closets, storage areas, attics, and the like. It also provides a restful way to dim-down and darken an infant's or infirm persons room.